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Satellite images show that since the 1970s the extent of Antarctic sea ice has increased at a rate of 100,000 square kilometres a decade.
The new research helps explain why observed changes in the amount of sea-ice cover are so different in both polar regions.
The Antarctic ice sheet is losing as much as 36 cubic miles of ice a year in a trend that scientists link to global warming, according to a new paper that provides the first evidence that the sheet's total mass is shrinking significantly.
Using satellite images of sea ice and computer models the scientists discovered that the ozone hole has strengthened surface winds around Antarctica and deepened the storms in the South Pacific area of the Southern Ocean that surrounds the continent. This resulted in greater flow of cold air over the Ross Sea (West Antarctica) leading to more ice production in this region.
Originally posted by MorfeuZ
I just came across this article on a new study that claims Antartica Ice cap is increasing by large amounts because of what? THE OZONE LAYER! WTF?!?
I thought that the official history was that the south pole ice cap was shrinking like the north pole ice cap.
Ice sheets are bigger than ice shelves or glaciers. Masses of ice covering less than 50,000 km² are termed an ice cap. An ice cap will typically feed a series of glaciers around its periphery.
Originally posted by MorfeuZ
reply to post by melatonin
Thank you for pointing this to me. Although maybe you could clarify what you meant with "continental sea ice cap", cause your definition seems to be different from what I found.
You mean that although the Ice extent might be increasing, the whole ice sheet might be loosing mass by getting thinner?
Do you have any links supporting this?
Regards.
Published Online March 2, 2006
Science DOI: 10.1126/science.1123785
Science Express Index
Reports
Submitted on December 13, 2005
Accepted on February 21, 2006
Measurements of Time-Variable Gravity Show Mass Loss in Antarctica
Isabella Velicogna 1* and John Wahr 2*
1 University of Colorado and CIRES, UCB 390, Boulder, CO 80309-0390, USA; Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 300-233, Pasadena, CA 91109-8099, USA.
2 University of Colorado and CIRES, UCB 390, Boulder, CO 80309-0390, USA.
* To whom correspondence should be addressed.
Isabella Velicogna , E-mail: [email protected]
John Wahr , E-mail: [email protected]
Using measurements of time-variable gravity from the Gravity Recovery and Climate Experiment (GRACE) satellites we determine mass variations of the Antarctic ice sheet during 2002-2005. We find that the ice sheet mass decreased significantly, at a rate of 152 ± 80 km3/year of ice, equivalent to 0.4 ± 0.2 mm/year of global sea level rise. Most of this mass loss came from the West Antarctic Ice Sheet.
Nature Geoscience 1, 106 - 110 (2008)
Published online: 13 January 2008 | doi:10.1038/ngeo102
Subject Categories: Climate science | Cryospheric science
Recent Antarctic ice mass loss from radar interferometry and regional climate modelling
Eric Rignot1,2,3, Jonathan L. Bamber4, Michiel R. van den Broeke5, Curt Davis6, Yonghong Li6, Willem Jan van de Berg5 & Erik van Meijgaard7
Large uncertainties remain in the current and future contribution to sea level rise from Antarctica. Climate warming may increase snowfall in the continent's interior1, 2, 3, but enhance glacier discharge at the coast where warmer air and ocean temperatures erode the buttressing ice shelves4, 5, 6, 7, 8, 9, 10, 11. Here, we use satellite interferometric synthetic-aperture radar observations from 1992 to 2006 covering 85% of Antarctica's coastline to estimate the total mass flux into the ocean. We compare the mass fluxes from large drainage basin units with interior snow accumulation calculated from a regional atmospheric climate model for 1980 to 2004. In East Antarctica, small glacier losses in Wilkes Land and glacier gains at the mouths of the Filchner and Ross ice shelves combine to a near-zero loss of 461 Gt yr-1. In West Antarctica, widespread losses along the Bellingshausen and Amundsen seas increased the ice sheet loss by 59% in 10 years to reach 13260 Gt yr-1 in 2006. In the Peninsula, losses increased by 140% to reach 6046 Gt yr-1 in 2006. Losses are concentrated along narrow channels occupied by outlet glaciers and are caused by ongoing and past glacier acceleration. Changes in glacier flow therefore have a significant, if not dominant impact on ice sheet mass balance.
So, overall, the antarctic ice sheet is losing mass, but there is an increase in sea ice.
To infer the ice sheet's mass, the team measured ice flowing out of Antarctica's drainage basins over 85 percent of its coastline. They used 15 years of satellite radar data from the European Earth Remote Sensing-1 and -2, Canada's Radarsat-1 and Japan's Advanced Land Observing satellites to reveal the pattern of ice sheet motion toward the sea. These results were compared with estimates of snowfall accumulation in Antarctica's interior derived from a regional atmospheric climate model spanning the past quarter century.
Using satellite images of sea ice and computer models the scientists discovered that the ozone hole has strengthened surface winds around Antarctica and deepened the storms in the South Pacific area of the Southern Ocean that surrounds the continent. This resulted in greater flow of cold air over the Ross Sea (West Antarctica) leading to more ice production in this region.
Originally posted by MorfeuZ
I would not say it IS loosing mass neither that it IS increaing sea ice extent.
It all depends on the accuracy of these models, right?
Would you have any info if these models are accurate? Since climate models are very very complex and rely heavely on accurate data. For example, the north pole rapid ice loss has contradicted all models where it was previously tested.
I mean, I created this thread to discuss these apparent (to me) discrepancies, there seems to be a lot of uncertainties left on these subjects.
Regards.
Originally posted by MorfeuZ
But you were right, I did mix apples and oranges on the first post. Is there any way I can edit out this error now? I don't see an edit button anymore.
But you now see that there probably isn't any discrepency? The sea ice and the ice sheet are different things.
Anyway, yeah, if you play up the uncertainties sufficiently, the reality can disappear...apparently.